Refining hydrocarbon oil



Patented Aug. 28, 1934 PATENT, osmos- REFINWG HYDROCABBON OIL Robert E. Manley and Howard H. Gross, Beacon, N. Y., assignors to The Texas Company, New York, N. Y., a corporation of Delaware No Drawing.

Claims.

This invention relates to refining hydrocarbon oil, and more particularly to refining mineral oil by solvent extraction.

The invention contemplates the treatment and 5 refining of mineraloil with mixed solvents containing furfural; by the use of certain solvent mixtures containing furfural themineral oil may be separated by the extraction method to produce oil fractions having desired characteristics and w substantially free from undesired components.

A solvent liquid suitable for mixing with the furfural, in accordance with our invention, comprises a solvent selected from the amyl amines such, for example, as mono-amyl amine or diamyl amine.

We have found that in treating and purifying mineral oil by extraction with furfural, the furfural may be used more effectively when mixed with a solvent liquid of the type mentioned above,

which liquid, when used by itself, may have quite dissimilar or divergent selective solvent action upon the oil undergoing treatment.

The furiural and solvent liquid of disslmila selective action may be mixed in any desired proportion to produce a solvent liquid mixture having .any desired selective action 'upon the particular oil undergoing treatment. In this way,

it is possible to obtain from a given mineral oil standing. One layer will comprise raflin'ate or. that portion of the oil insoluble in the furfural. 1

while the other will comprise the extract portion which is soluble in the furfural. Both layers may ao'contain substantial amounts of the modifying solvent liquid, depending upon the extent to which it is miscible with the oil undergoing treatment.

The individual layers after separation may be 46 removed and the solvent liquid recovered therefrom, or they may be'subiected to further treatment with additional quantities of solvent liquid.

By subiecting the separated fractionsto repeated extraction, aseries of fractions of differing char- 50 acter may be separated from-the original oil.

This is of particular advantage in connection with the extracting of mineral oil forthe production of lubricating oils of differing lubricating properties. Lubricating oil fractions are usu-' ally composed of various groups of hydrocarbons,

will depend upon the degree of separation desired and may. for example,'range'from around Application December 9, i932, Serial No.646,489

cific gravity and highviscosity index, while the latter are characterized by having a heavy gravity and low viscosity index. Oils of high viscosity index, in other words, having a flat temperature viscosity relationship possess superior lubricating value for some purposes, as, for example, in the lubrication of internal combustion 65 engines.

Lubricating fractions as obtained from crude petroleum usually also contain objectionable constituents in the form of aromatic and unsaturated compounds as well as sulphur-bearing bodies. The removal of these constituents is desirable in order to produce products of low sulphur content and free from readily oxidizable bodies which tend, during use, to form sludge. Thus, in the manufacture of lubricating oils. we 7 have found that mixtures of furfural with solvent liquids selected from the amyl amines are effective in extracting these objectionable bodies as well as those constituents having a low viscosity index and thus produce lubricating oil products characterized by having a high degree of stability and a high viscosity index.

Moreover, it is possible, by varyingthe proportion of amine to furfural, to either increase or decrease the extent of extraction as, for example, the degree of separation between the paramnic and naphthenic bodies. In this way, lubricating oil products of characteristics, such as viscosity index, may be produced as desired.

By way of example, in practicing our invention, one part of untreated lubricating oil distillate derived from a Mid-continent crude by distillation underdiminished pressure, is mixed with about two parts of a solvent liquid mixture 95. composed of about equalparts of furfural and an amyl amine, such as mono-amyl amine or diamyl amine. This mixture is subjected to ash. tation and heating in order to produce a homogeneous mixture or to effect complete solution of the oil in the solvent.

The mixture is then allowed to settle, forming an upper and a lower layer. The temperature at which this separation into two layers is effected 0 F. to 200 F. or higher.

In some instances, it may be desirable to heat the mixture to a relatively high temperature in i order to obtain complete solution of the oil in the solvent, and then allow the mixture to cool to a desired temperature where, upon settling, separating into two layers results The upper layer will comprise the undissolved hydrocarbons or those constituents of the oil characterized by having a relatively high viscosity index, .while the lower layer will be composed of soluble hydrocarbons and constituents of low viscosity index dissolved in the bulk of the solvent liquid mixture.

. The layers are then separately withdrawn and the solvent liquid removed from the oil by vacuum distillation or by other suitable means. If desired, the separated layers may be subjected to treatment with additional quantities of the solvent or additional quantities of the solvent liquid mixture composed of furfural and amine in proportions differing from those used in the initial extracting step. In this way, it is possible to obtain from the lubricating oil distillate a series of fractions of differing viscosity index, and other characteristics as may be desired.

The lubricating oil distillate may be subjected to the foregoing extraction treatment either before or after dewaxing by any of the well known methods for the separation of wax from waxbearing mineral oil.

The invention is not restricted to mixing with the furfural an amine solvent having relatively less selective action but may embrace mixing therewith a solvent having either'greater or less selectivity, or possesing a selective action upon certain constituents from which the furfural may exert little or no solvent action. It has been found that furfural is more selective toward naphthenic hydrocarbons of 'high viscosity than toward naphthenic hydrocarbons of low viscosity, and

. therefore, it is of advantage to use, in admixture with the furfural, a solvent liquid having somevwhat the opposite range of selectivity. Ac-

cordingly, a combination of such solvents offers.

an advantage for the more complete removal of both light and heavy fractions of naphthenes .from a wide range of naphthenic or paraflinic lubricating oil fractions.

' Furthermore, the invention is not'necessarily limited to the'treatment of lubricating'oil fractions but may be applied to the refining and purification of various hydrocarbon or mineral oil fractions, including naphtha, kerosene, etc., as well as various residual or distillate fractions or products derived from petroleum or other sources. It isalso applicable to the treatment and purification of the crude petroleum itself.

Under ordinary conditions, the extraction treat ment with a mixture comprising furfural and an amyl amine may be applied to a raw distillate or oil fraction to produce a finished merchantable product. However, in the case of oils of exceedingly high sulphur content or unusual characteristics, as regards sludge or carbon-forming tendencies, it may be found desirable to supplement the treatment by the usual acid, alkali and doctor treatment, applied either before or after the treatment with the solvent mixture.

Obviously many modifications and variations of the invention, as hereinbefore set forth, may be made without departing from the spirit and scope thereof, and therefore only such limitations should be imposed as arev indicated in the appended claims.

We claim:

1. The method of refining and purifying mineral oil to separate sulphur-bearing bodies, aromatic, unsaturated compounds and other undesired bodies from the relatively more parafiinic portion of the oil which comprises extracting the oil with furfural in admixture with asolvent selected from the amyl amines whereby the oil is separated into a refined oil fraction having desired characteristics and an extract fraction containing the undesired constituents.

2. The method of refining and purifying mineral oil to separate sulphur-bearing bodies, aromatic, unsaturated compounds and other undesired bodies from the relatively more parafilnic portion of the oil which comprises extracting the oil with furfural in admixture with mono-amyl amine whereby the oil is separated into a refined oil fraction having desired characteristics and an extract fraction containing the undesired constituents.

3. The method of refining and purifying mineral oilto separate sulphur-bearing bodies, aromaticj unsaturated compounds and other undesired bodies from the' relatively more parafiinic portion of the oil which comprises extracting the oil with furfural in admixture with di-amyl amine whereby the oil is separated intoa refined oil fraction having desired characteristics and an extract fraction containing the undesired constituents.

4. The method of refining and purifying mineral oil to separate sulphur-bearing bodies, aromatic. unsaturated compounds and other undesired bodies from the relatively more parafiinic portion of the oil which comprises extracting the oil with a selective solvent mixture composed of a substance comprising essentially furfural in admixture with an amyl amine whereby the oil is separated'into a refined oil fraction having desired characteristics and an extract fraction containing the undesired constituents. I

5. In the manufacture of lubricating oil from mineral oil containing both low viscosity index and high viscosity index constituents the method of separating therefrom fractions of differing viscosity index comprising extracting the oil with a selective solvent mixture composed of a substance comprising essentially furfural in admixture with an amyl-amine whereby the oil is separated into fractions respectively rich in low viscosityindex and high'viscosity index constituents.

ROBERT E. MANLEY. HOWARD H. GROSS. 

